Transition period for image transitions in a media file

1. A method for processing image data, comprising:

performing a conversion between a visual media file and a bitstream, wherein the visual media file comprises image items each comprising a sequence of pictures according to a media file format, and wherein the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format,

wherein the media file format specifies that an operating point information (OPI) network abstraction layer (NAL) unit is absent in an image item having a specific image item type or samples of the image item, and

wherein the media file format further specifies that, in response to a record of operating points being included in a property descriptor of the operating points that indicates high-level characteristics of the bitstream, at least one of a value of a first syntax element in the record or a value of a second syntax element in the record is constrained to be a predetermined value.

2. The method of claim 1 , wherein the conversion includes encoding the visual media file into the bitstream.

3. The method of claim 1 , wherein the conversion includes decoding the visual media file from the bitstream.

4. The method of claim 1 , wherein the specific image item type is associated with a Versatile Video Coding (VVC) standard.

5. The method of claim 1 , wherein the specific image item type is specified as ‘vvs1’.

6. The method of claim 1 , wherein a suggested transition period associated with an image item to be applied for a transition between the image item and a next image item during displaying of the pictures as a slideshow;

wherein the suggested transition period is specified as an M-bit unsigned integer value in units of 1/X seconds, where M is equal to 8 and X is a power of 2 and X is greater than 2, and

wherein the image item is pointed by an entity ID value which is included in a slideshow entity group, multiple entity ID values of multiple image items in the slideshow entity group are listed in an increasing display order, and the visual media file includes one or multiple slideshow entity groups with different group ID values.

7. The method of claim 6 , wherein the suggested transition period is specified in units of 1/16 seconds.

8. The method of claim 6 , wherein the suggested transition period is further specified for each transition property or each type of transitions.

9. The method of claim 1 , wherein the first syntax element specifies a maximum temporal identification associated with an i-th profile tier level syntax structure, i being in a range of 0 to (a number of profile tier levels−1), and wherein the second syntax element specifies a maximum temporal identification associated with the record of the operating points.

10. The method of claim 9 , wherein the first syntax element is represented as ptl_max_temporal_id[i], and wherein the second syntax element is represented as max_temporal_id.

11. The method of any of claim 1 , wherein the predetermined value is equal to 0.

12. An apparatus for processing visual media file data comprising a processor and a non-transitory memory with instructions thereon, wherein the instructions upon execution by the processor, cause the processor to:

perform a conversion between a visual media file and a bitstream, wherein the visual media file comprises image items each comprising a sequence of pictures according to a media file format, and wherein the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format,

wherein the media file format specifies that an operating point information (OPI) network abstraction layer (NAL) unit is absent in an image item having a specific image item type or samples of the image item, and

wherein the media file format further specifies that, in response to a record of operating points being included in a property descriptor of the operating points that indicates high-level characteristics of the bitstream, at least one of a value of a first syntax element in the record or a value of a second syntax element in the record is constrained to be a predetermined value.

13. The apparatus of claim 12 , wherein the specific image item type is associated with a Versatile Video Coding (VVC) standard.

14. The apparatus of claim 12 , wherein the specific image item type is specified as ‘vvs1’.

15. The apparatus of claim 12 , wherein a suggested transition period associated with an image item to be applied for a transition between the image item and a next image item during displaying of the pictures as a slideshow;

wherein the suggested transition period is specified as an M-bit unsigned integer value in units of 1/X seconds, where M is equal to 8 and X is a power of 2 and X is greater than 2, and wherein the image item is pointed by an entity ID value which is included in a slideshow entity group, multiple entity ID values of multiple image items in the slideshow entity group are listed in an increasing display order, and the visual media file includes one or multiple slideshow entity groups with different group ID values.

16. The apparatus of claim 15 , wherein the suggested transition period is specified in units of 1/16 seconds.

17. The apparatus of claim 15 , wherein the suggested transition period is further specified for each transition property or each type of transitions.

18. A non-transitory computer-readable storage medium storing instructions that cause a processor to:

perform a conversion between a visual media file and a bitstream, wherein the visual media file comprises image items each comprising a sequence of pictures according to a media file format, and wherein the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format,

wherein the media file format specifies that an operating point information (OPI) network abstraction layer (NAL) unit is absent in an image item having a specific image item type or samples of the image item, and

wherein the media file format further specifies that, in response to a record of operating points being included in a property descriptor of the operating points that indicates high-level characteristics of the bitstream, at least one of a value of a first syntax element in the record or a value of a second syntax element in the record is constrained to be a predetermined value.

19. A non-transitory computer-readable recording medium storing a bitstream comprising image items which is generated by a method performed by a video processing apparatus, wherein the method comprises:

generating the bitstream from a visual media file,

wherein the visual media file comprises image items each comprising a sequence of pictures according to a media file format, and wherein the bitstream comprises access units each comprising one or more pictures each belonging to a layer according to a video coding format,

wherein the media file format specifies that an operating point information (OPI) network abstraction layer (NAL) unit is absent in an image item having a specific image item type or samples of the image item, and

wherein the media file format further specifies that, in response to a record of operating points being included in a property descriptor of the operating points that indicates high-level characteristics of the bitstream, at least one of a value of a first syntax element in the record or a value of a second syntax element in the record is constrained to be a predetermined value.